The sans.font.family isn't used in practice; it is only listed for
completeness. The symbol and dingbat families should probably not be
changed. That leaves you with the body, title and monospace families to
find suitable fonts for.

For English and other Western languages, “serif”
translates to Times New Roman in the PDF, “sans-serif” to
Helvetica/Arial, and “monospace” to Courier. These fonts, as
well as the Symbol font, are supported by all Adobe PDF readers. That's
why Western docwriters don't have to take any special measures to get
their language represented correctly. But most non-Western characters
aren't present in the Adobe standard fonts. If you don't supply the fonts
yourself, the tools will build the PDF without complaints, but every
character not present in the standard font will be replaced with a
“#”, making your text look like this: ####
## #### #### ##### ## ## #####.

It is advised that you choose fonts that are widely present on
computer systems in your country. Metrics and configuration files are
committed to CVS and can be reused by every doc builder, but the font
files themselves are not. They must be present – and locatable – on the
user's system every time a PDF is built. (Note: only when it's
built, not when it's
read!)

If your language or script doesn't make a distinction between serif
and sans-serif fonts, feel free to pick the same font for the body and
title families – or use another distinction which is appropriate in your
language. But do try to use another font for the monospace family, even if
the difference between proportional (variable-width) and monospaced
(fixed-width) fonts is meaningless in your situation. The point is that
monospaced text is often used within sentences, to make certain words
stand out from the rest.

Every font chosen should support these styles and weights: normal,
italic, bold, and bold italic. (Again, in as far as these are valid
concepts in your language.) Sometimes these variations are housed in one
single font file, sometimes they are distributed over up to four files.
Only Type 1 and TrueType fonts can be used.

Because of the tremendous differences between the world's many
languages and scripts, it's impossible to give any more specific
instructions here. But feel free to discuss any problems or questions
regarding this on the firebird-docs list.

Once you've decided on the fonts to use, make a note of the file
locations. TrueType font files typically have the extension .ttf, TrueType collections .ttc. Type 1 font files have extensions
.pfb (the font itself) and
.pfm (the metrics info). To embed
Type 1 fonts, you need both the .pfb and the .pfm.